Efficacy of methylchloro/methylisothiazolone biocide againstLegionella pneumophila in cooling tower water

McCoy, William F.; Wireman, John W.; Lashen, E. S.

doi:10.1007/bf01569416

Cited by 10 publications

(6 citation statements)

References 15 publications

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“…In this respect, the concentrations of CMIT employed in these experiments are higher than those generally used in water treatment (ca. 10 ,ug/ml) (27) and the concentrations of PHMB are 10 to 20% of those employed in its major application of swimming pool sanitation (ca. 10 p,g/ml) (38).…”

Section: Resultsmentioning

confidence: 99%

“…Legionella pneumophila is ubiquitous in aquatic environments and may serve as a source of human infection when found in association with air conditioning machinery, cooling towers, and water systems in large buildings. Rigorous regimes of temperature control and chlorination of hot and cold water systems (7,11) and chemical treatment of cooling towers (24,27) are generally employed to combat the presence of microorganisms but have failed to eradicate legionellae from such plants. Contributory to the recalcitrance of legionellae in water systems is its growth within an adherent biofilm comprising numerous other bacterial species, protozoa, and ciliates (25).…”

mentioning

confidence: 99%

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Relationship between Legionella pneumophila and Acanthamoeba polyphaga: physiological status and susceptibility to chemical inactivation

Barker¹,

Brown²,

Collier³

et al. 1992

Appl Environ Microbiol

160

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Survival studies were conducted on Legionella pneumophila cells that had been grown intracellularly in Acanthamoeba polyphaga and then exposed to polyhexamethylene biguanide (PHMB), benzisothiazolone (BIT), and 5-chloro-N-methylisothiazolone (CMIT). Susceptibilities were also determined for L. pneumophila grown under iron-sufficient and iron-depleted conditions. BIT was relatively ineffective against cells grown under iron depletion; in contrast, iron-depleted conditions increased the susceptibilities of cells to PHMB and CMIT. The activities of all three biocides were greatly reduced against L. pneumophila grown in amoebae. PHMB (1x MIC) gave 99.99%o reductions in viability for cultures grown in broth within 6 h and no detectable survivors at 24 h but only 90 and 99.9% killing at 6 h and 24 h, respectively, for cells grown in amoebae. The antimicrobial properties of the three biocides against A. polyphaga were also determined. The majority of amoebae recovered from BIT treatment, but few, if any, survived CMIT treatment or exposure to PHMB. This study not only shows the profound effect that intra-amoebal growth has on the physiological status and antimicrobial susceptibility of L. pneumophila but also reveals PHMB to be a potential biocide for effective water treatment. In this respect, PHMB has significant activity, below its recommended use concentrations, against both the host amoeba and L. pneumophila.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Relationship between Legionella pneumophila and Acanthamoeba polyphaga: physiological status and susceptibility to chemical inactivation

Barker¹,

Brown²,

Collier³

et al. 1992

Appl Environ Microbiol

160

View full text Add to dashboard Cite

show abstract

“…To eradicate legionellae in cooling tower water, several methods, including ultraviolet irradiation, have been tested ( 1,6,9,14,15). Susceptibility of L. pneumophila to UV-radiation was reported (1,8), but this method is not yet in practical use as a biocidal treatment of cooling tower water, because the quartz glass surface quickly becomes dirty in filthy water and inhibits the penetration of ultraviolet light.…”

mentioning

confidence: 99%

Effects of FLONLIZER®, Ultraviolet Sterilizer, on Legionella Species Inhabiting Cooling Tower Water

Yamamoto

Urakami²,

Nakano³

et al. 1987

Microbiology and Immunology

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Legionella pneumophila in sterile distilled water was not detected after ultraviolet irradiation by FLONLIZER®, a new‐type sterilizer, at a flow rate of 82.5 to 364.8 liters/hr. When irradiated by FLONLIZER® at a flow rate of under 324.0 liters/hr, no viable cells of legionellae, other heterotrophic bacteria and bacterivorous protozoa were detected in the cooling tower water, which was found to contain L. pneumophila. No viable cells of L. pneumophila and L. bozemanii suspended in sterile distilled water were detected after the irradiation with UV‐doses of over 6.16 × 103 μW·sec/cm2. At the irradiation of low UV‐doses under 1.06 × 104 μW·sec/cm2, the viable count of legionellae recuperated by photoreactivation from UV‐damage increased with the exposure time under a white fluorescent lamp. However, in the samples irradiated with UV‐doses of over 3.52 × 104 μW·sec/cm2, equal to the FLONLIZER®, legionellae did not recuperate even after 18 hr illumination with a white fluorescent lamp. FLONLIZER® is thus expected to act as a sterilizer which can control the legionellae inhabiting cooling tower systems placed in outdoor space.

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“…Within two weeks of the addition, however, the population size of these microorganisms, including legionellae, recovered to the same level as before. The effects of many chemicals, including such oxidizing biocides as hydrogen peroxide (2) and various organic biocides, such as halogen compounds (4,(6)(7)(8), on legionellae have been tested in laboratory studies. We also have made similar experiments (data not shown).…”

mentioning

confidence: 99%

“…Cooling towers have often been implicated as a source for the production of aerosol containing viable legionellae (3). The efficiency of biocidal treatments by chemicals (2,4,(6)(7)(8) and ultraviolet irradiation (10) is known in preventing the growth of legionellae in laboratory studies. To estimate the effects of these treatments, we surveyed microorganisms in coolingtower water during tower operation in summer.…”

mentioning

confidence: 99%

Effects of Biocidal Treatments to Inhibit the Growth of Legionellae and Other Microorganisms in Cooling Towers

Yamamoto

Ezaki

Ikedo

et al. 1991

Microbiology and Immunology

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The effects of biocidal treatments for cooling towers were examined through the use of chemicals and ultraviolet irradiation to inhibit the growth of legionellae and other microorganisms. In the water of cooling towers without continuous biocidal treatments, heterotrophic bacteria and bacterivorous protozoan first appeared, and then legionellae increased up to 104 CFU/100 ml. When a UV sterilizer was connected to the cooling tower, the legionellae count was 1/10 or 1/100 of that in the nontreated tower water. In the water of towers supplemented continuously with the biocidal chemicals, legionellae were not found during a 4-month period. The biocidal treatments tested were proved to suppress the increase of legionellae in cooling-tower water, and thus are useful in preventing the outbreak of legionellosis due to inhalation of contaminated aerosol from the cooling tower system.

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Efficacy of methylchloro/methylisothiazolone biocide againstLegionella pneumophila in cooling tower water

Cited by 10 publications

References 15 publications

Relationship between Legionella pneumophila and Acanthamoeba polyphaga: physiological status and susceptibility to chemical inactivation

Relationship between Legionella pneumophila and Acanthamoeba polyphaga: physiological status and susceptibility to chemical inactivation

Effects of FLONLIZER®, Ultraviolet Sterilizer, on Legionella Species Inhabiting Cooling Tower Water

Effects of Biocidal Treatments to Inhibit the Growth of Legionellae and Other Microorganisms in Cooling Towers

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